The general purpose is to study problems related to the function of the lungs in disease. More specifically we are interested in four areas: 1) The main thrust continues to be concerned with pulmonary gas exchange, especially oxygen diffusion in disease. The disease under study hs changed from chronic obstructive lung disease to catastrophic lung disease (shock lung, oxygen toxicity). The method of study continues to require the measurement of arterial oxygen while the patient breathes several inspired oxygen mixtures and the use of the Bohr integral isopleth concept. 2) The change in sensitivity of the respiratory center in pulmonary disease, and in some electrolyte disorders will be studied by means of the CO2 response curve. 3) Pulmonary function in teenagers with kyphoscoliosis will continue to be studied before and after spine straightening operations. These operations have cosmetic value: we hope to ascertain whether they improve pulmonary function. 4) We will continue to study patients with alpha-l-antitrypsin deficiency paying particular attention to exceptions to general rules, e.g., homozygotes with good lung function late in life.